When I COLD start my car my wideband reads in the high 13's but within 8-10 seconds it gradually moves up to 18 .. and then it goes to a

----- ----- -----

Reading..

Once it has done that it stays that way until the car cold soaks..

If the car is warm at all it will read --- --- --- as soon as I start it..

Even under boost it does not change..

Its an AEM unit.

Is it b.c. the sensor is bad and once it heats up it quits reading or what..

What else could it be..

 

First off if it goes from 13 to 18 the car would be running lean not rich, and buy a bosch sensor its like 50$

 

**** my bad.. lean.. But if it was actually running that lean wouldnt it get hot among other things..

Yes, Im going to get one I just wanted to make sure it was the sensor first..
I wanted to see if any one else has seen this happen before..

 

When mine went bad it would only read until i floored it then it would read nothing, sensors go bad, ive changed them around once a year

 

No. Lean mixtures have less energy (less heat) than stoich mixtures. You would know if you are running that lean as you would be experiencing lean misfires.

Are you still running closed loop with the factory narrow band sensor?

 

no its tuned on s300 no narrow band

 

Another sensor is $80

 

You can still enable closed loop with open loop trigger conditions via load or RPM vs TPS conditions. Whether or not your tuner enabled this you would have to pull your calibration to see.